This application is based on Patent Application No. 2001-157657 filed May 25, 2001 in Japan, the content of which is incorporated hereinto by reference.
1. Field of the Invention
The present invention relates generally to a socket for an IC package. More particularly, the invention relates to a socket for an IC package having a retainer mechanism which can satisfactorily manage contact between terminals of the IC package and contacts of the socket.
2. Description of the Related Art
Conventionally, in a socket for a so-called BGA (Ball grid array) type IC package, in which IC package terminals are formed by hemisphere bumps projecting from a lower surface of the IC package body, there has been a socket employing a plurality of latches. The latches are opened in response to lowering of a retaining cover arranged in an upwardly and downwardly movable condition relative to the socket body. The latches force contact between the IC package body and the plurality of latches biased by springs during an upward movement of the retaining cover. This clamps the IC package body between a mounting surface of the socket body and the latches to attain a predetermined contact pressure between IC package terminals and contacts.
However, in the conventional socket of the form clamping the IC package body between the mounting surface of the socket body and the latches, the IC package body is forced to the mounting surface of the socket body by the latches. It is therefore possible to cause deformation or damage to the IC package body due to fluctuation of the urging force and other causes.
On the other hand, fine metal particles that are created in association with contact between the IC package and the contacts that can accumulate on the mounting surface of the socket body. When the IC package is forced onto the mounting surface, such fine metal particles can be deposited on the IC package to potentially cause shorting between the IC package terminals in the worst case.
Furthermore, since the IC package body is forced by a plurality of spring biased latches, if spring forces are different, biasing forces to be applied to respective latches become different. This may result in causing tilting of the IC package or lateral displacement thereof to impair predetermined contact between the contacts and the IC package terminals.
It is an object of the present invention to provide a socket for an IC package which can solve the problems set forth above.
In an aspect of the present invention, there is provided a socket for an IC package comprising:
a socket body having a receptacle portion of the IC package and contacts arranged on a bottom surface of the receptacle portion and resiliently displaceable in up and down directions;
a latch pivotably provided in the socket body and being biased toward the receptacle portion by spring means;
latch releasing means, provided for relative movement with respect to the socket body, for moving the latch away from the receptacle portion against spring force applied by the spring means; and
motion magnitude restricting means for restricting motion magnitude of the latch toward the bottom surface of the receptacle portion.
Here, the receptacle portion may be formed in a positioning base formed separately from the socket body and exchangeable, and the motion magnitude restricting means may be formed at a top portion of the positioning base.
In another aspect of the present invention, there is provided a socket for an IC package comprising:
a socket body having a quadrangular IC package receptacle portion and a plurality of contacts arranged in a bottom surface of the receptacle portion and resiliently displaceable in up and down directions;
a pair of latches pivotably provided in the socket body and being biased toward the receptacle portion by spring means;
latch releasing means, provided for relative movement with respect to the socket body, for moving the pair of latches away from the receptacle portion against the spring means; and
motion magnitude restricting means for restricting motion magnitude of the pair of latches toward the bottom surface of the receptacle portion.
With one aspect of the present invention, the IC is package is loaded in the condition where the latch is distanced from the receptacle portion against the spring means by the latch releasing means. The IC package is temporarily received within the receptacle portion in a condition where the IC package is arranged on the bottom surface of the receptacle portion and is placed on the contacts resiliently displaceable in up and down directions. In this condition, when the latch releasing means is released, the latch is biased by the spring means toward the receptacle portion as biased by the spring means to downwardly depress the IC package. Associating with depression by the latch, the IC package is lowered to resiliently displace the contacts. Since motion amount of the latch toward the bottom surface of the receptacle portion of the IC package is restricted to the predetermined value by the motion magnitude restricting means, the IC package is stopped at the predetermined position and the IC package body is never urged onto the bottom surface of the receptacle.
Accordingly, even when fluctuation is caused in biasing force by the spring means, the IC package body is never deformed or damaged. Also, fine metal particle will never deposit on the IC package body. Also, the IC package is not inclined or laterally offset so as not to cause failure of predetermined contact between the contacts and the terminals of the IC package.
It should be noted that, with the preferred construction of the present invention, the receptacle portion is formed within the exchangeable positioning base which is formed separately from the socket body. Since the motion magnitude restricting means is formed at the top portion of the positioning base, it is possible to adapt to the configuration of the IC package (dimension and thickness) only by exchanging the position base.
The above and other objects, effects, features and advantages of the present invention will become more apparent from the following description of embodiments thereof taken in conjunction with the accompanying drawings.